U.S. patent number 9,170,118 [Application Number 14/065,478] was granted by the patent office on 2015-10-27 for navigation system for electric vehicle.
This patent grant is currently assigned to HITACHI, LTD.. The grantee listed for this patent is HITACHI, LTD.. Invention is credited to Yuki Horita, Noboru Kiyama, Tatsuaki Osafune, Keisuke Shirai, Satoshi Shirasawa.
United States Patent |
9,170,118 |
Kiyama , et al. |
October 27, 2015 |
Navigation system for electric vehicle
Abstract
A navigation system for an electric vehicle includes a
telematics center, a display terminal, and a charging station. In
response to a request from the display terminal, the telematics
center sends a route search result, which is created based on
information on an electric vehicle and the charging station and
which includes base point information whose remaining battery
capacity is to be confirmed, to the display terminal. The display
terminal displays route guidance information, the current position,
and a result of comparison between the current remaining battery
capacity and the base point information to the user who is driving
the electric vehicle.
Inventors: |
Kiyama; Noboru (Tokyo,
JP), Shirai; Keisuke (Tokyo, JP),
Shirasawa; Satoshi (Tokyo, JP), Osafune; Tatsuaki
(Tokyo, JP), Horita; Yuki (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI, LTD. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
HITACHI, LTD. (Tokyo,
JP)
|
Family
ID: |
49485668 |
Appl.
No.: |
14/065,478 |
Filed: |
October 29, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140163877 A1 |
Jun 12, 2014 |
|
Foreign Application Priority Data
|
|
|
|
|
Dec 7, 2012 [JP] |
|
|
2012-267769 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
58/12 (20190201); G01C 21/3469 (20130101); G01C
21/3697 (20130101); B60L 53/65 (20190201); B60L
2240/622 (20130101); Y02T 10/7072 (20130101); Y02T
90/169 (20130101); B60L 2260/44 (20130101); B60L
2260/52 (20130101); B60L 2250/16 (20130101); Y02T
10/72 (20130101); Y02T 90/12 (20130101); B60L
2240/72 (20130101); B60L 2260/54 (20130101); Y02T
90/167 (20130101); Y02T 90/14 (20130101); Y04S
30/14 (20130101); Y02T 90/16 (20130101); Y02T
10/70 (20130101); B60L 2240/80 (20130101); B60L
2250/12 (20130101) |
Current International
Class: |
G01C
21/34 (20060101); G01C 21/36 (20060101) |
Field of
Search: |
;701/533,537 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2 600 106 |
|
Jun 2013 |
|
EP |
|
2007-050888 |
|
Mar 2007 |
|
JP |
|
2007-534124 |
|
Nov 2007 |
|
JP |
|
2012-211888 |
|
Nov 2012 |
|
JP |
|
2013-085449 |
|
May 2013 |
|
JP |
|
2012/014615 |
|
Feb 2012 |
|
WO |
|
Primary Examiner: Nguyen; Nga X
Attorney, Agent or Firm: Volpe and Koenig, P.C.
Claims
The invention claimed is:
1. A navigation system for an electric vehicle, said navigation
system comprising a display terminal that sends and receives
information to and from an electric vehicle over a network; and a
server that sends and receives information to and from said display
terminal over the network, wherein said display terminal performs
processing for sending a search request for a route, via which said
electric vehicle moves from a starting point to a destination, to
the server, the search request including position coordinates of
the starting point, position coordinates of the destination, a
remaining battery capacity, a battery capacity, and a start time;
processing for displaying route guidance information on an output
device, the route guidance information sent from said server, the
route guidance information created based on a route search result
that includes one or more pieces of base point information;
processing for displaying, on said output device, a result of
comparison between an estimated remaining battery capacity which
indicates a band including a maximum value and a minimum value of a
remaining battery capacity, which is assumed when the electric
vehicle passes a battery state confirmation point, which is
included in one of the pieces of the base point information, with a
confirmation-point remaining battery capacity of said electric
vehicle at the confirmation point; and processing for requesting
said server to perform a route re-search according to whether the
confirmation-point remaining battery capacity when the electric
vehicle passes the confirmation point becomes smaller than the
minimum value of the band or larger than the maximum value of the
band, and said server performs processing for searching for a
route, via which said electric vehicle moves from the starting
point to the destination without battery exhaustion, in response to
the route search request or the route re-search request from said
display terminal; processing for calculating the range of the
estimated remaining battery capacity including the maximum value
and the minimum value to be included in the base point information;
processing for deriving one or more pieces of the base point
information on the searched-for route and for adding the derived
base point information to the route search result, said base point
information including position information on the confirmation
point and the estimated remaining battery capacity at the
confirmation point; and processing for sending the route search
result, which includes the derived base point information, to the
display terminal.
2. The navigation system for an electric vehicle according to claim
1, wherein said server performs processing for setting a position
on the searched-for route as the confirmation point, the position
being dependent on a time, a distance, a power consumption, or
intersection point information.
3. The navigation system for an electric vehicle according to claim
1, wherein said server further performs processing for calculating
the band of a remaining battery capacity, which is assumed when the
electric vehicle passes the point, as the base point information
using travel history of the electric vehicle and other electric
vehicles that have passed the base point position.
4. The navigation system for an electric vehicle according to claim
1, wherein said server performs processing for searching for a
plurality of routes, on each of which a charging station is
available and the electric vehicle can travel from the starting
point to the destination without battery exhaustion, in the route
search processing in which a plurality of remaining battery
capacities are set; and processing for deriving a junction point
for two route search results whose remaining battery capacity
levels are closest to each other and, with the point as a base
point, calculating base point information, which includes position
information, estimated remaining battery capacity at the point, and
information on a new transit charging station when the route is
changed, and for adding the calculation result to the route search
result, the junction point being a point used to classify the route
into a part where the route is common and a part where the route is
not common and said display terminal performs processing for
displaying, during route guidance, a current-position remaining
battery capacity of said electric vehicle that is moving, the base
point information included in the route search result, and the
information on a new transit charging station when the route is
changed.
5. The navigation system for an electric vehicle according to claim
1, wherein said server further performs processing for deriving the
confirmation point based on a time, a distance, a power
consumption, or position information on an intersection.
6. A display terminal that sends and receives information to and
from an electric vehicle over a network, said display terminal
performing: processing for managing by associating a position, a
type, and an output power of a charging station with an identifier
that can uniquely identify the charging station; processing for
managing road information for use in a route search; processing for
searching for a route via which the electric vehicle moves from a
starting point to a destination without battery exhaustion based on
acquired position coordinates of the starting point, position
coordinates of the destination, a remaining battery capacity, a
battery capacity, and a start time; processing for setting a
position on a searched-for route as a battery state confirmation
point, the position being dependent on a time, a distance, a power
consumption, or position information on an intersection, and for
calculating a band including a maximum value and a minimum value of
a remaining battery capacity, which is assumed when the electric
vehicle passes the confirmation point, as the estimated remaining
battery capacity; processing for deriving one or more pieces of
base point information that includes position information on the
confirmation point and a confirmation-point remaining battery
capacity at the point; and processing for confirming a remaining
battery capacity of the electric vehicle and for displaying, on a
output device, a result of comparison between an estimated
remaining battery capacity at the confirmation point included in
one of the pieces of the base point information and a
confirmation-point remaining battery capacity of the electric
vehicle at the confirmation point; and processing for performing
the route re-search processing according to whether the
confirmation-point remaining battery capacity when the electric
vehicle passes the confirmation point becomes smaller than the
minimum value of the band or becomes larger than the maximum value
of the band.
7. The display terminal according to claim 6 wherein said display
terminal further performs processing for deriving the confirmation
point based on a time, a distance, a power consumption, or position
information on an intersection.
Description
INCORPORATION BY REFERENCE
The present application claims priority from Japanese application
JP2012-267769 filed on Dec. 7, 2012, the content of which is hereby
incorporated by reference into this application.
BACKGROUND OF THE INVENTION
The subject disclosed herein relates to a navigation service for an
electric vehicle.
Recently, automobile manufacturers are actively engaged in the
development and marketing of an electric vehicle (EV, with any
number of wheels) that travels using electric power stored
in-vehicle batteries. Unlike a conventional gasoline-powered
vehicle, an electric vehicle does not use fossil fuel. In addition,
an electric vehicle can use a power generation method, such as
atomic power generation or solar energy generation, that emits less
carbon dioxide. Therefore, switching from a gasoline-powered
vehicle to an electric vehicle is an effective countermeasure
against global warming and fossil fuel exhaustion. This prompts the
governments of various nations of the world, including Japan,
Europe, and America, to adopt tax reduction systems or subsidy
systems for the diffusion of electric vehicles.
However, the distance (cruising range) over which an electric
vehicle can travel with one charging of the batteries is about 200
km that is shorter than that of a gasoline-power vehicle. This
means that the driver of an electric vehicle must visit charging
stations, which correspond to the gas stations of a gasoline-power
vehicle, more frequently when traveling long distances.
Charging stations are classified roughly into two types: normal
charging station and rapid charging station. Although widely
available, a normal charging station requires four to eight hours
for one charging. Therefore, a normal charging station is
unsuitable for a charging facility that is used away from home. On
the other hand, though one charging requires only 30 minutes, a
rapid charging station is not widely used today because it requires
a special facility that is very expensive.
For the reasons described above, an electric vehicle user, who is
planning to travel to a distant location, must be careful about the
remaining battery capacity and the charging station locations
during traveling. These worries may prevent an electric vehicle
from becoming popular.
To solve these problems, efforts are being made to increase the
capacity of the in-vehicle batteries and to increase the number of
charging facilities. At the same time, to compensate for the
shortcomings described above, the study has been conducted on the
telematics service that works with a navigation system mounted in
an electric vehicle.
For example, JP-A-2012-211888 proposes a terminal that informs the
user about the requirement of charging and the charging stations
available on a route. More specifically, this terminal displays a
bar graph, the left end of which corresponds to the current
position and which has a length corresponding to the maximum
battery charging capacity, for displaying the battery remaining
capacity of the electric vehicle. On this bar graph, the terminal
displays the current remaining battery capacity, the battery
capacity required to reach the destination, the shortage of battery
capacity that is the difference the two, and the charging stations
to which the vehicle can reach with the current remaining battery
capacity (Paragraphs 0051 to 0055).
SUMMARY OF THE INVENTION
According to the conventional technology, a route is changed to
prevent the battery of an electric vehicle from running out (out of
power condition), for example, by searching for a route on which
charging stations are available or by changing a route to another
route on which the battery consumption is low.
However, because the left end of the bar graph corresponds to the
current position, the problem with the technology disclosed in
JP-A-2012-211888 is that the user who is driving an electric
vehicle cannot determine whether the electric vehicle has been
traveling smoothly as expected at the time of scheduling (or at the
time of last charging). This makes the user feel uneasy.
Another problem is that the user also feels uneasy about the
navigation that changes a route search because sufficient
information is not provided for the reason for changing the
route.
Eco-driving refers to driving that contributes to cost saving in
electricity. This is achieved by saving power consumption, for
example, by increasing the pre-set temperature of an air
conditioner during the summer and decreasing it during the winter,
withholding the use of peripheral apparatuses such as audiovisual
apparatuses, and avoiding quick acceleration, or by increasing the
amount of electric power generation by avoiding quick deceleration
and using the regenerative brake.
The technology disclosed in this specification relates to a
navigation system that informs the user whether the current
remaining battery capacity of an electric vehicle is within the
range assumed by the route guidance being carried out.
The disclosed system is characterized in that, for the route search
result, base point information is calculated as a point, at which
the remaining battery capacity is confirmed, according to the
relation between the remaining battery capacity and the position of
a charging station. The base point information includes the
position information as well as the information on the upper limit
and the lower limit on the remaining battery capacity to be
reserved when the vehicle passes the point.
In the disclosed system, when an electric vehicle starts traveling
based on an actual route search result, a terminal that performs
the navigation function repeatedly compares the position and the
remaining battery capacity at that time with the base point
information described above. Before the electric vehicle passes a
base point, the system displays the estimated information that will
be generated when the electric vehicle passes the base point.
When the electric vehicle passes a base point, the system displays
the information indicating the comparison between the upper and
lower limits of the estimated remaining battery capacity and the
actual remaining battery capacity. In addition, when the actual
remaining battery capacity of the electric vehicle is higher than
the estimated upper limit value or lower than the lower limit
value, the system performs the route research.
A specific embodiment is a navigation system for an electric
vehicle, the navigation system including a display terminal that
sends and receives information to and from an electric vehicle over
a network; and a server that sends and receives information to and
from the display terminal over the network, wherein
the display terminal performs processing for sending a search
request for a route, via which the electric vehicle moves from a
starting point to a destination, to the server, the search request
including position coordinates of the starting point, position
coordinates of the destination, a remaining battery capacity, a
battery capacity, and a start time; processing for displaying route
guidance information on an output device, the route guidance
information sent from the server, the route guidance information
created based on a route search result that includes one or more
pieces of base point information; and processing for displaying, on
the output device, a result of comparison between an estimated
remaining battery capacity at a battery state confirmation point,
which is included in one of the pieces of the base point
information, with a confirmation-point remaining battery capacity
of the electric vehicle at the confirmation point and
the server performs processing for searching for a route, via which
the electric vehicle moves from the starting point to the
destination without battery exhaustion, in response to the route
search request from the display terminal;
processing for deriving one or more pieces of the base point
information on the searched-for route and for adding the derived
base point information to the route search result, the base point
information including position information on the confirmation
point and a confirmation-point remaining battery capacity at the
confirmation point; and processing for sending the route search
result, which includes the derived base point information, to the
display terminal.
The server performs processing for setting a position on the
searched-for route as the confirmation point, the position being
dependent on a time, a distance, a power consumption, or
intersection point information.
Another specific embodiment is a display terminal that sends and
receives information to and from an electric vehicle over a
network, the display terminal performing:
processing for managing by associating a position, a type, and an
output power of a charging station with an identifier that can
uniquely identify the charging station; processing for managing
road information for use in a route search; processing for
searching for a route via which the electric vehicle moves from a
starting point to a destination without battery exhaustion based on
acquired position coordinates of the starting point, position
coordinates of the destination, a remaining battery capacity, a
battery capacity, and a start time; processing for setting a
position on a searched-for route as a battery state confirmation
point, the position being dependent on a time, a distance, a power
consumption, or position information on an intersection, and for
deriving one or more pieces of base point information that includes
position information on the confirmation point and a
confirmation-point remaining battery capacity at the point; and
processing for confirming a remaining battery capacity of the
electric vehicle and for displaying, on a output device, a result
of comparison between an estimated remaining battery capacity at
the confirmation point included in one of the pieces of the base
point information and a confirmation-point remaining battery
capacity of the electric vehicle at the confirmation point.
According to the above embodiments, the user who is driving an
electric vehicle can easily determine whether the vehicle is
traveling as scheduled in a scheduled route using the current
remaining battery capacity at the current position.
When changing a route for preventing battery exhaustion, the system
presents information on a charging station on a new route in
advance as the base point information, eliminating the worry about
the reason for changing the route.
When eco-driving is performed by the user more efficiently than is
indicated by the route search result, the system evaluates the
eco-driving and allows the user to re-search for a better route.
This leads to an increase in service quality for electric vehicle
users.
The technology disclosed in this specification provides an electric
vehicle service that gives the user a sense of security.
Other objects, features and advantages of the invention will become
apparent from the following description of the embodiments of the
invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing an example of the general configuration
of a navigation system for an electric vehicle.
FIG. 2 is a diagram showing an example of the internal
configuration of a telematics center.
FIG. 3 is a diagram showing an example of the internal
configuration of a display terminal.
FIG. 4 is a diagram showing an example of the internal
configuration of an electric vehicle.
FIG. 5 is a diagram showing an example of the internal
configuration of a charging station.
FIG. 6 is a diagram showing an example of a user information DB and
a charging station information DB processed by the telematics
center.
FIG. 7 is a diagram showing an example of a probe information DB
and a road link information DB processed by the telematics
center.
FIG. 8 is a diagram showing an example of a sequence of the route
search request processing among the display terminal, the
telematics center, the electric vehicle, and the charging
station.
FIG. 9 is a diagram showing an example of a flowchart of the route
search processing at the telematics center.
FIG. 10 is a diagram showing an example of route search results
obtained by the route search processing at the telematics
center.
FIG. 11 is a diagram showing an example of a flowchart of the
navigation processing at the display terminal.
FIG. 12 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
FIG. 13 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
FIG. 14 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
FIG. 15 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
FIG. 16 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
FIG. 17 is a diagram showing an example of a flowchart of the route
search processing at the telematics center.
FIG. 18 is a diagram showing an example of the screen configuration
on the output device of the display terminal.
DESCRIPTION OF THE EMBODIMENTS
Embodiments are described below with reference to FIG. 1 to FIG.
18.
FIG. 1 is a diagram showing an example of the configuration of a
navigation system for an electric vehicle disclosed in this
embodiment.
An electric vehicle described in this specification is a vehicle
that uses electricity, stored in the chargeable secondary
batteries, as the energy source and rotates the motor with the
electricity to generate power for traveling. The electric vehicle
may have any number of wheels.
The system includes a telematics center device (hereinafter called
a server or a telematics center) 100 that is a server device for
collecting and processing information (INF), a display terminal 101
that accepts a user input and displays a map, the locations of
charging stations, route search results, and navigation information
on the screen, and a charging station 103 that charges an electric
vehicle 102. These components are interconnected over a network
104.
The network 104 is a mobile phone network, the Internet, or a
short-range wireless communication such as a LAN, or a network
composed of a combination of these networks.
FIG. 2 is a diagram showing an example of the internal
configuration of the telematics center 100.
The telematics center 100 includes a memory 200 to or from which
the CPU writes and reads data during program execution, a CPU 201
that executes a program, read into the memory 200, for performing
the processing described below, a storage device 202 such as a hard
disk in which a navigation information generation program 205 is
stored, a communication unit 203 that communicates with the display
terminal 101 or other devices over the network 104, and an internal
communication line 204 such as a bus via which the modules are
connected.
The navigation information generation program 205 includes programs
that implement a route search request acceptance unit 210, a
charging station information acquisition unit 211, a shortest route
search unit 212, and a probe information receiving unit 213.
A user management DB (data base) 220, a vehicle management DB 221,
a charging station management DB 222, a probe DB 223, a road link
DB 224, and a map DB 225 are stored in the storage device 202. When
required for the program execution of the navigation information
generation program 205, these DBs are read into the memory 200 as
necessary.
Data received via the communication unit 203 is passed to the route
search request acceptance unit 210 or the probe information
receiving unit 213 when the data is received from the display
terminal 101, and to the charging station information acquisition
unit 211 when the data is received from the charging station
103.
When a request is received from the display terminal 101, the route
search request acceptance unit 210 executes the shortest route
search unit 212. Using the charging station information stored in
the charging station management DB 222, the probe information
stored in the probe DB 223, the road information stored in the road
link DB 224, and the map and slope information stored in the map DB
225, the shortest route search unit 212 searches the routes, via
which the electric vehicle 102 can reach from the starting point to
the destination using the current remaining battery capacity (SoC:
State of Charge) without battery exhaustion, for a route that
requires the shortest travel time including the charging time.
Then, the shortest route search unit 212 sends the route search
result to the display terminal 101 via the communication unit 203
and the network 104.
When a route search request is received from the display terminal
101, the charging station information acquisition unit 211 collects
information on the charging facility usage status and usage
schedule status (hereinafter called availability information) from
a plurality of charging station 103 and stores the collected
information in the charging station management DB 222.
The probe information receiving unit 213 receives the probe
information from the display terminal 101 and stores the received
probe information in the probe DB 223.
FIG. 3 is a diagram showing an example of the internal
configuration of the display terminal 101.
Referring to FIG. 3, the display terminal 101 includes a memory 300
to or from which the CPU writes and reads data during program
execution, a CPU 301 that executes a program, read into the memory
300, for performing the processing described below, a storage
device 302 such as a hard disk in which a navigation information
display program 307 is stored, an input device 303 such as a
keyboard and a mouse, an output device 304 such as a display, a
communication device 305 that carries out communication with the
telematics center 100 and the electric vehicle 102 over the network
104, and an internal communication line 306 such as a bus via which
the modules are connected. The input device 303, such as a touch
panel, may be integrated into the output device 304.
The navigation information display program 307 includes the
programs that implement a route information acquisition unit 310, a
navigation processing unit 311, a vehicle information acquisition
unit 312, and a probe information sending unit 313.
A map DB 320 is stored in the storage device 302. A part or the
whole of map information is read into the memory 300 as necessary
whenever it is required during the program execution of the
navigation information display program 307.
Data received via the communication device 305 is passed to the
route information acquisition unit 310 when the data is received
from the telematics center 100, and to the vehicle information
acquisition unit 312 when the data is received from the electric
vehicle 102.
When a user's route search request, which includes information on
the starting point and the destination, is received via the input
device 303, the route information acquisition unit 310 sends the
information on the starting point, the destination, the remaining
battery capacity, and the battery capacity to the telematics center
100 as a route search request. After that, the route information
acquisition unit 310 outputs the route search result received from
the telematics center 100, as well as the map information stored in
the map DB 320, to the output device 304.
The navigation processing unit 311 guides the electric vehicle 102
to the destination when the electric vehicle 102 starts traveling
based on the route search information acquired by the route
information acquisition unit 310. In addition, the navigation
processing unit 311 outputs to the output device 304 the
information as to whether the pace of the battery consumption of
the electric vehicle 102, which is currently traveling, is faster
or slower than the pace expected by the route search result in a
format the user can understand quickly.
Depending upon the comparison result, there is a possibility that
the battery will run out or that the optimal route has been changed
to another route because the battery power is sufficient. In such a
case, the navigation processing unit 311 calls the route
information acquisition unit 310 as necessary during route guiding
to update the route search result to the latest result.
When a user's route search request is received via the input device
303 or a request is received from the navigation processing unit
311, the vehicle information acquisition unit 312 acquires
information on the remaining battery capacity and the battery
capacity of the user's electric vehicle 102. This information is
required by the route information acquisition unit 310.
FIG. 4 is a diagram showing an example of the internal
configuration of the electric vehicle 102.
Referring to FIG. 4, the electric vehicle 102 includes a memory 400
to or from which the CPU writes and reads data during program
execution, a CPU 401 that executes a program, read into the memory
400, for performing the processing described below, a secondary
storage device 402 such as a hard disk in which a vehicle
information control program 407 is stored, a GPS sensor 403 that
acquires the location information on the vehicle, a battery
controller 404 that controls the charging/discharging of the
batteries of the electric vehicle 102 and acquires information on
the current remaining battery capacity and the battery capacity, a
communication device 405 that carries out communication with the
telematics center 100 over the network 104, and an internal
communication line 406 such as a bus and a controller area network
(CAN) via which the modules are connected.
The vehicle information control program 407 includes a program that
implements a vehicle information request acceptance unit 410.
Data received via the communication device 405 is passed to the
vehicle information request acceptance unit 410 if the data is
received from the display terminal 101.
When a request is received from the display terminal 101, the
vehicle information request acceptance unit 410 acquires the
location positioning result from the GPS sensor 403, acquires
information on the current battery remaining capacity and the
battery capacity from the battery controller 404, and sends the
acquired information to the telematics center 100 via the
communication device 405 and the network 104.
FIG. 5 is a diagram showing an example of the internal
configuration of the charging station 103.
Referring to FIG. 5, the charging station 103 includes a memory 500
to or from which the CPU writes and reads data during program
execution, a CPU 501 that executes a program, read into the memory
500, for performing the processing described below, a storage
device 502 such as a hard disk in which a charging station
information control program 506 is stored, a charging plug
controller 503 that performs the charging/discharging control of
one or more charging plugs, a communication device 504 that carries
out communication with the telematics center 100 over the network
104, and an internal communication line 505 such as a bus via which
the modules are connected.
The charging plugs are connected to the charging plug controller
503. When the charging station 103 has multiple types of plugs or
multiple plugs of the same type, the corresponding number of
charging plugs are connected to the charging plug controller
503.
The charging station information control program 506 includes the
programs that implement an availability information request
acceptance unit 510 and an availability information management unit
511.
An availability information management DB 520, stored in the
storage device 502, is read into the memory 500 as necessary
whenever it is required for the program execution of the charging
station information control program 506.
Data received via the communication device 504 is passed to the
availability information request acceptance unit 510 if the data is
received from the telematics center 100.
The availability information management unit 511 manages a charging
schedule time at which the electric vehicle 102, currently
connected to the charging plug, will use the charging station and
stores that information in the availability information management
DB 520.
The charging station 103 may have the charging-station usage
reservation function. For example, a possible configuration of the
charging station 103 is that the charging station 103 includes an
input device such as a touch panel for allowing the user to make a
charging time reservation on the screen or that the display
terminal 101 connects to the charging station 103 via the network
104 and the communication device 504 to allow the user to make a
charging time reservation for the charging station 103.
When a request is received from the telematics center 100, the
availability information request acceptance unit 510 sends a part
of the availability information, as well as the charging station
identifier (hereinafter called a charging station identifier
(CSID)), to the telematics center 100 via the communication device
504 and the network 104. This availability information, stored in
the availability information management DB 520, is information on
the time zones, beginning at the current time, for which the usage
is scheduled. When the charging station 103 has a plurality of
charging plugs, each plug has a unique CSID.
FIG. 6 is a diagram showing an example of the format (600-603) of
the user management DB 220 and an example of the format (610-616)
of the charging station management DB 222. These DBs are managed by
the telematics center 100.
In the user management DB 220 in FIG. 6, the numeral 600 indicates
a user ID that is an identifier uniquely identifying a user, the
numeral 601 indicates the last date/time at which the information
on the user with the identifier in numeral 600 was acquired last,
the numeral 602 indicates the position information that is the
acquired user information, and the numeral 603 indicates the usage
status that is the acquired user information.
In the charging station management DB 222 in FIG. 6, the numeral
610 indicates a CSID that is an identifier uniquely identifying a
charging station, the numeral 611 indicates the information on the
position where the charging station is located, the numeral 612
indicates the type of the charging method of the charging station,
the numeral 613 indicates the output power of the charging station,
the numeral 614 indicates the connector shape of the plug used at
the charging station, the numeral 615 indicates the availability
information that is the availability information and the waiting
time information on the charging station, and the numeral 616
indicates the last acquisition date/time at which the information
on the charging station was acquired.
FIG. 7 is a diagram showing an example of the format (700-705) of
the probe DB 223 and an example of the format (710-716) of the road
link DB 224. These DBs are managed by the telematics center
100.
In the probe DB 223 in FIG. 7, the numeral 700 indicates a probe ID
700 that is an identifier uniquely identifying collected probe
information, the numeral 701 indicates a road link ID indicating a
road for which the probe information is collected, the numeral 702
indicates a passage time that is a time at which the probe
information was generated, the numeral 703 indicates a passage-time
remaining battery capacity indicating the remaining battery
capacity when the probe information was generated, the numeral 704
indicates a passage-time electric mileage that is electric mileage
information on the electric vehicle 102 when the probe information
was generated, and the numeral 705 indicates a last-transit CSID
that identifies a charging station at which the electric vehicle
102, which generates the probe information, visited last.
In the road link DB 224 in FIG. 7, the numeral 710 indicates a road
link ID that is an identifier uniquely identifying road
information, the numeral 711 indicates the position information on
the entry-side end of the road, the numeral 712 indicates the
position information on the exit-side end of the road, the numeral
713 indicates the traveling time required to travel on the road
from position information 1 to position information 2, the numeral
714 indicates the traveling distance, the numeral 715 indicates the
required battery capacity, and the numeral 716 indicates the name
of the road.
The required battery capacity in the numeral 715 is calculated
using the information, such as the slope information, stored in the
map DB 225.
The traveling time 713 and the required battery capacity 715 may be
changed in real time by the telematics center 100 that calculates
them using the traffic congestion information.
FIG. 8 shows the flow of the route search execution processing and
the search result display processing performed in the navigation
system for an electric vehicle. The processing is performed among
the route information acquisition unit 310 and the vehicle
information acquisition unit 312 of the display terminal 101, the
route search request acceptance unit 210, charging station
information acquisition unit 211, and shortest route search unit
212 of the telematics center 100, the vehicle information request
acceptance unit 410 of the electric vehicle 102, and the
availability information request acceptance unit 510 of the
charging station 103.
In FIG. 8, the vehicle information acquisition unit 312 of the
display terminal 101 requests the user's electric vehicle 102,
which provides the navigation function, to send vehicle information
(S800). The vehicle information acquisition unit 312 identifies the
user's electric vehicle 102 based on the vehicle identification
number (hereinafter called a VIN). That is, the vehicle information
acquisition unit 312 searches the electric vehicles around the
display terminal for an electric vehicle having a VIN that is
registered in the electric vehicle and that matches a VIN
registered in the display terminal. At this time, it is also
possible to request the user to enter the VIN of the electric
vehicle 102, which is used by the user, via the input device
303.
The vehicle information request acceptance unit 410 of the electric
vehicle 102 receives the vehicle information request from the
display terminal 101 (S810). After that, the vehicle information
request acceptance unit 410 acquires the information on the current
remaining battery capacity and the battery capacity from the
battery controller 404 and sends the acquired information to the
display terminal 101 as the vehicle information (S811). The vehicle
information request acceptance unit 410 may also acquire the
location positioning result from the GPS sensor 403 of the electric
vehicle 102 and sends the vehicle information, including the
acquired location positioning information, to the display terminal
101 as necessary. In addition, the vehicle information request
acceptance unit 410 may also send the vehicle information, which
includes the possible traveling distance (electric mileage) per 1
kWh of the electric vehicle 102, to the display terminal 101 as
necessary.
The vehicle information acquisition unit 312 of the display
terminal 101 receives the vehicle information sent from the vehicle
information request acceptance unit 410 of the electric vehicle 102
(S801). After that, the route information acquisition unit 310
acquires the information on the scheduled start time, starting
point, and destination from the user via the input device 303 and
sends a route search request, in which the acquired information as
well as the acquired vehicle information are included, to the
telematics center 100 (S802).
The scheduled start time included in the route search request, sent
from the route information acquisition unit 310 to the telematics
center 100, may be the current time indicated by the clock included
in the display terminal 101 or the electric vehicle 102. Instead of
including the scheduled start time in the route search request, the
request acceptance time indicated by the clock included in the
telematics center 100 may also be used as the scheduled start
time.
The starting point included in the route search request sent from
the route information acquisition unit 310 to the telematics center
100 may be the current position of the electric vehicle 102.
The starting point included in the route search request sent from
the route information acquisition unit 310 to the telematics center
100 may be the current position of the user who has the display
terminal 101. In this case, the display terminal 101 is supposed to
have a GPS sensor mounted thereon, and the position information
obtained from the GPS sensor is used as the starting point.
Any information other than a VIN may also be used to identify the
electric vehicle 102 when the information uniquely identifies the
vehicle. For example, when the telematics center 100 has the user
management DB in which the correspondence between user identifiers
(USERID) and VINs is stored, a USERID may be used in place of a
VIN. In addition, to acquire the vehicle information in S800-S801,
the display terminal 101 and the electric vehicle 102 may
communicate with each other via the telematics center. For example,
the display terminal 101 sends a USERID to the telematics center
100. Upon receiving the USERID, the telematics center 100
identifies the VIN associated with the received USERID, requests
the electric vehicle 102 with the identified VIN to send the
vehicle information, and then delivers the received vehicle
information to the display terminal 101.
In place of means for acquiring vehicle information in S800 to S801
by means of the vehicle information acquisition unit 312, it is
also possible to request the user to enter vehicle information from
the input device 303, in which case the entered value is used as
the vehicle information.
The route search request acceptance unit 210 of the telematics
center 100 receives the route search request from the route
information acquisition unit 310 of the display terminal 101
(S820). When the route search request is received, the charging
station information acquisition unit 211 requests all charging
stations 103 to send the availability information related to a
period of time within .alpha. hours beginning at the scheduled
start time obtained in S820 (S821). .alpha. specifies a time zone
of availability information to be acquired, for example, a 24-hour
period of time beginning at the scheduled start time.
The charging stations 103, to which the charging station
information acquisition unit 211 sends an availability information
inquiry, may be limited based on the distance between the starting
point and the destination or on the cruising range of the electric
vehicle derived from the remaining battery capacity and the
electric mileage. The charging station information acquisition unit
211 may send an availability information inquiry to the charging
stations not only at a route search request reception time. For
example, the charging station information acquisition unit 211 of
the telematics center 100 may send an availability information
inquiry to the charging stations 103 at regular intervals.
The availability information request acceptance unit 510 of the
charging station 103 receives the availability information request
from the charging station information acquisition unit 211 of the
telematics center 100 (S830). The availability information request
acceptance unit 510 obtains a charging schedule, which is included
in the period of time within .alpha. hours beginning at the start
time, from the availability information management DB 520 and sends
the obtained charging schedule to the telematics center 100
(S831).
The charging station information acquisition unit 211 of the
telematics center 100 receives the charging station information
from the availability information request acceptance unit 510 of
the charging station 103 and then stores the received availability
information in the charging station management DB 222 (S822). If
the availability information is not used, the processing in S821 to
S822 may be omitted.
After that, the shortest route search unit 212 of the telematics
center 100 uses the vehicle information and the route search
request information, obtained in S820, to search for a route on
which the charging stations are available and requires the shortest
traveling time that includes the charging time and the wait time
for charging (S823). The detailed processing in S823 is described
later with reference to FIG. 9. The route search request acceptance
unit 210 sends the route search result, obtained in S823, to the
display terminal 101 (S824). If the display terminal 101 does not
include the map DB 320, the route search request acceptance unit
210 may send the route search result to the display terminal 101
with the map information on the area of the route search result
attached as necessary.
The route information acquisition unit 310 of the display terminal
101 receives the route search result from the route search request
acceptance unit 210 of the telematics center 100 (S803). Then, the
route information acquisition unit 310 outputs the received route
search result, as well as the map information obtained from the map
DB 320, to the output device 304 (S804). After that, in order to
start the navigation (route guidance) processing that is described
later with reference to FIG. 11, the navigation processing unit 311
is started (S805).
The navigation processing (S805) need not always be started
immediately after the route information acquisition unit 310
displays the result in S804. Instead, the selection screen may be
displayed on the output device 304 to allow the user to select
whether to start navigation, in which case the navigation
processing is started when the user selects to start navigation on
the input device 303.
FIG. 9 is a diagram showing the flow of the processing S823 of the
shortest route search unit 212 of the telematics center 100 in the
navigation system for an electric vehicle, and FIG. 10 is a diagram
showing the items of the route search result obtained by the
shortest route search unit 212.
In FIG. 9, the shortest route search unit 212 uses the information
obtained in S820 and S822 (starting point, destination, current
remaining battery capacity, and battery capacity and, as necessary,
the availability information on the charging stations or traffic
information (congestion information)) to search the routes, on
which zero or more charging stations are available, for a route
that requires the shortest traveling time (including the charging
time) while avoiding battery exhaustion during the travel from the
starting point to the destination (S900).
As a method for searching for a route that requires the shortest
traveling time (inclining charging time), JP-A-2006-112932
discloses the following method. "The distance from the current
position of an electric vehicle to a charging facility and the
distance from the charging facility to the destination are
calculated respectively from the map information in the database
unit, the capacity required for traveling the calculated distance
is calculated based on the electric mileage of the electric
vehicle, the capacity to be charged at the charging facility is
calculated from the required capacity and the remaining in-vehicle
battery capacity, and the charging time required for charging the
capacity is calculated based on the information on the charging
performance of the charging facility (paragraph 0018)".
The route search result obtained in S900 includes the following
information. (1) Position information on the starting point and the
destination and, as necessary, the position information on a
transit charging station and the information on the charging time
at the transit charging station, and the information on the total
traveling time and the total traveling distance, (2) Information
described in Table 1000 in FIG. 10; that is, the information on
which intersections the vehicle will pass through to arrive at the
destination, an intersection (I/S) ID 1001 described in the order
of intersections through which the vehicle will pass through,
position information 1002 on the intersection, estimated traveling
distance 1003 from the starting point to the intersection,
estimated traveling time 1004 from the starting point to the
intersection, estimated remaining battery capacity 1005 that is the
estimated value of the remaining battery capacity when the vehicle
arrives at the intersection, and guiding information 1006 on the
traveling direction (turn right/left turn, go straight ahead) when
the vehicle travels from the intersection to the next intersection,
and (3) Road link information that is stored in the road link DB
224 as the road information between intersections and is a part of
information required for linking between the intersections.
Next, by performing the processing in S901 to S908, the shortest
route search unit 212 adds the information on a confirmation point
(checkpoint: CP, also called a base point) to the route search
result, wherein the checkpoint is a base point for confirming the
battery status to check whether the currently moving electric
vehicle is driving at a satisfactory battery consumption rate.
First, with the identification number, n, of the checkpoint
information set to 1, the shortest route search unit 212 performs
calculation for the first checkpoint (S901). Based on the estimated
traveling time described in Table 1000, the shortest route search
unit 212 identifies the information on a section between two
intersections (that is, the road link information) through which
the vehicle will pass when the traveling time from the starting
point becomes n times the predetermined value .DELTA. and then
extracts the road link ID 710 (S902).
The server may set an appropriate value as the predetermined time
.DELTA., or the user may specify the value of .DELTA. and send a
route search request with the specified information included in the
request. The shortest route search unit 212 searches the probe DB
223 for a plurality of probe IDs 700, each of which is associated
with the road link ID 701 that matches the road link ID 710
extracted in S902, and extracts those entries as the data used to
derive the remaining battery capacity that should be reserved at
the passage time (S903).
In addition, the shortest route search unit 212 extracts a
plurality of pieces of probe data each of which has the
last-transit CSID 705 that matches the transit charging station
included in the route search result obtained in S900 (S904). The
extracted data indicates that one or more electric vehicles,
including this vehicle and other vehicles, actually passed the
location and arrived at the charging station in the past. The
shortest route search unit 212 derives the maximum value and the
minimum value of the passage-time remaining battery capacity 703 of
the extracted probe data group to identify the range of the
estimated remaining battery capacity band estimated at route search
time (at the time the driving plan is created) in which the
remaining battery capacity should be included when the vehicle
passes the checkpoint (S905).
When the derivation of the n-th checkpoint information is
completed, the shortest route search unit 212 adds 1 to n (S906)
and checks whether n times the predetermined time .DELTA. is
smaller than the total traveling time to see if the next checkpoint
should be derived (S907). If n times the predetermined time .DELTA.
is smaller than the total traveling time (S907: YES), the shortest
route search unit 212 returns to S902 to generate the next
checkpoint information. If n times the predetermined time .DELTA.
is larger than the total traveling time, the shortest route search
unit 212 includes the extracted (n-1) pieces of checkpoint
information in the route search result and terminates the
processing (S908).
The checkpoint information, such as that shown in Table 1010 in
FIG. 10, includes a checkpoint ID 1011 that indicates the order of
checkpoints from the starting point, position information 1012 that
is checkpoint position information such as position information 1
(711) or position information 2 (712) of the corresponding road
link or the midpoint of those two positions, a remaining battery
capacity upper limit 1013 and a remaining battery capacity lower
limit 1014 that indicate the estimated remaining battery capacity
band at checkpoint passage time derived in S905, an estimated
traveling distance 1015 from the starting point to the checkpoint,
and an estimated traveling time 1016 from the starting point.
When identifying a road link in S902 and S907 for determining a
checkpoint, the estimated traveling distance or the estimated
battery consumption amount may also be used as the base instead of
using the estimated traveling time. More specifically, .DELTA. may
be the distance or the power amount instead of the time. In
addition, the position of a checkpoint for the confirmation may be
determined based, not on the distance or the battery consumption
amount, but on the intersections. For example, all intersections
may be a checkpoint, or the battery status may be confirmed at
every 10 intersection or at 100 m ahead of an intersection.
A limitation may be placed on the probe data, from which data is
extracted in S903 and S904, based on a time at which traveling
history was registered. One of the methods is to use only probe
data whose passage time 702 includes a date/time later than one
year ago today.
A limitation may be placed on the probe data, from which data is
extracted in S903 and S904, based on the VIN of the electric
vehicle 102 that registered probe data. One of the methods is to
use only probe data on the electric vehicle 102 owned by the user
of the display terminal 101 from which a route search request was
received or to use only data registered by the electric vehicle 102
that is the same vehicle type as that of the electric vehicle 102
of the user who issued a route search request. In the case of this
example, the probe data in the probe DB 223 stores information on
the VIN of the electric vehicle 102 that registered probe data and
the vehicle management DB 221 stores information on the VIN and the
vehicle type for each electric vehicle 102.
When identifying the estimated remaining battery capacity band
determined in S903 to S905, the probe data need not always be used.
Instead, the values in a predetermined range may also be used based
on the estimated remaining battery capacity 1005 corresponding to
the intersection ID 1001; for example, a value 3% higher than the
base remaining battery capacity may be used as the upper limit
value, and a value 7% lower than the base remaining battery
capacity as the lower limit value. When entering a route search
request, the user may also specify a fixed width of the estimated
remaining battery capacity band.
The lower limit value of the estimated remaining battery capacity
band may be determined based on the estimated remaining battery
capacity 1005 of the intersection ID 1001. That is, the lower value
may be calculated by subtracting the estimated remaining battery
capacity, which is the remaining capacity at the time the vehicle
arrives at the destination or at a transit charging station, from
the base remaining battery capacity. The lower limit value may also
be the minimum battery capacity determined based on a charging
station that can be reached from the intersection ID 1001 with the
minimum battery consumption amount.
The upper limit value of the estimated remaining battery capacity
band may be the battery capacity required for the vehicle to reach
directly from the intersection ID 1001 to the destination.
When the user specifies a remaining battery capacity that will
remain when the vehicle arrives at the destination, the upper limit
value and the lower limit value of the estimated remaining battery
capacity band may be generated by adding the specified remaining
battery capacity respectively to the lower limit value and the
upper limit value.
Because the eco-driving level differs according to the user, the
value of the passage-time remaining battery capacity 703 obtained
from the probe data need not directly be used but may be corrected
by comparing the value of the passage-time electric mileage 704
with the value of the electric mileage of the electric vehicle 102
that is traveling.
The estimated remaining battery capacity band may be obtained by
statistically approximating the probe data. For example, for the
probe data group extracted in S903 and S904, the distribution of
the passage-time remaining battery capacity 703 is approximated to
the normal distribution. In this case, the values calculated as the
mean value.+-..delta. are used as the upper limit value and the
lower limit value of the estimated remaining battery capacity band
when the variance of the normal distribution is represented by the
square of .delta..
In S905, instead of deriving the estimated remaining battery
capacity band, the border value (border) of the estimated remaining
battery capacity, calculated based on the lower limit value, may
also be derived. In this case, the border at the checkpoint is
means a value that will cause battery exhaustion with a high
probability when the value falls below the remaining battery
capacity. The border may also be derived, not by directly using the
lower limit value, but by using the average of the upper limit
value and the lower limit value or using the median, mode, or
average of the passage-time remaining battery capacity 703 of the
extracted probe data group.
The number of pieces of checkpoint information actually given to
the route search information need not be n-1, but n-2, n-3, . . . ,
or n pieces of checkpoint information from the starting point or
the destination may be given. The information may be given to the
route search result by thinning out n-1 checkpoints in such a way
that the checkpoint interval becomes longer as the checkpoints are
nearer to or farther from the destination.
FIG. 11 is a diagram showing the flow of the processing S805
performed by the navigation processing unit 311 of the display
terminal 101 in the navigation system for an electric vehicle.
In FIG. 11, to start navigation based on the route search result
obtained in S803, the navigation processing unit 311 first sets the
checkpoint number to 1 as the number of the checkpoint to which the
vehicle first travels from the starting point (S1100).
Next, via the vehicle information acquisition unit 312, the
navigation processing unit 311 requests the electric vehicle 102,
which is being driven by the user, to send vehicle information
(S1101). When the request is received (S1120), the vehicle
information request acceptance unit 410 of the electric vehicle 102
sends the information obtained from the battery controller, such as
the remaining battery capacity and the battery capacity, to the
vehicle information acquisition unit 312 as the vehicle information
(S1121), the vehicle information acquisition unit 312 of the
display terminal 101 receives the information and passes the
received information to the navigation processing unit 311 (S1102).
The processing in S1101 to S1102 is equivalent to the processing
shown in S800 to S801.
Next, the navigation processing unit 311 compares the current
position of the current electric vehicle 102, obtained as the
received vehicle information, with the position information on the
checkpoint which is included in the route search result and to
which the vehicle is currently traveling (S1103). The navigation
processing unit 311 compares the two positions, for example, by
checking whether the difference both in latitude and in longitude
is a fixed value of .beta. or smaller.
The navigation processing unit 311 performs this comparison to
determine whether the current position almost coincides with the
checkpoint, that is, whether the vehicle indicated by the current
position is passing the checkpoint (S1104). If the vehicle is not
passing the checkpoint (S1104: NO), the navigation processing unit
311 determines that the vehicle is still traveling to the next
checkpoint, confirms the distance to the next checkpoint and the
estimated remaining battery capacity band at that checkpoint,
calculates the estimated remaining battery capacity when the
vehicle arrives at the next checkpoint, and displays the calculated
result on the output device 304 (S1105). The estimated remaining
battery capacity C when the vehicle arrives at the next checkpoint
is calculated as follows. C=S-Z*K/Y where, Y is the estimated
battery consumption mount from the starting point to the current
position included in the route search result, K is the estimated
battery consumption amount from the current position to the next CP
that can be derived from the route search result, Z is the battery
amount consumed from the starting point as a result of the actual
driving, and S is the current remaining battery capacity obtained
in S1102. "*" is a multiplication sign.
The navigation processing unit 311 sends, via the probe information
sending unit 313, the position information on the current position
and the remaining battery capacity, which are obtained as the
passage result, to the telematics center as the probe information
for use as the information to be provided to other electric
vehicles (S1106) and waits a fixed amount of time, for example, one
second, to interrupt the navigation processing (S1107). The probe
information receiving unit 213 of the telematics center 100
receives the probe information and stores it in the probe DB 223
(S1130).
The step in which the navigation processing unit 311 waits a fixed
amount of time in S1107, that is, the navigation processing
interrupt step, may be omitted. The processing for waiting a fixed
period of time may be performed, for example, immediately before
S1001.
The navigation processing unit 311 determines whether the position
information, identified by the vehicle information received from
the electric vehicle 102, indicates a position near the destination
or a transit charging station or indicates that the vehicle has
arrived at the destination or a transit charging station
(S1108).
If it is determined that the vehicle has not yet arrived at the
destination or a transit charging station (S1108: NO), the
navigation processing unit 311 executes processing again, beginning
at S1101, to continue the navigation processing.
If it is determined that the vehicle has arrived at the destination
or a transit charging station (S1108: YES), the navigation
processing unit 311 terminates the navigation and, via the probe
information sending unit 313, sends the information on the
destination or the transit charging station, at which the vehicle
has arrived, and the probe information, which has been sent, to the
telematics center, as the general traveling history (S1117). The
probe information receiving unit 213 of the telematics center,
which receives the probe information, uses the received information
to add the information to the last-transit CSID already registered
in the probe DB 223 (S1131).
The step S1108 for determining whether the vehicle has arrived at
the destination may be executed any time between S1102 and S1117,
for example, before S1103.
The values calculated in S1105 are optionally not displayed on the
output device 304 depending upon the positional relation between
the current position and the next checkpoint. For example, if the
distance to the next checkpoint is 1 km or longer or the traveling
time to the next checkpoint is 10 minutes or longer, the values are
optionally not displayed on the output device 304.
If it is determined in S1104 that the vehicle has passed a
checkpoint, the navigation processing unit 311 compares the
remaining battery capacity (confirmation-point remaining battery
capacity) acquired at checkpoint passage time with the estimated
remaining battery capacity band at the checkpoint, acquired at
route search time, to see if the confirmation-point remaining
battery capacity is within the estimated remaining battery capacity
band (S1109). If the confirmation-point remaining battery capacity
is within the estimated remaining battery capacity band (S1109:
YES), the navigation processing unit 311 displays the information,
which indicates that the vehicle is traveling on the route with a
satisfactory battery consumption amount, on the output device 304
of the display terminal 101 (S1110). In addition to the information
indicating that the vehicle is driving smoothly as expected, the
information on eco-driving may also be displayed. For example, if
the confirmation-point remaining battery capacity is currently in
the lower half of the estimated remaining battery capacity band,
the information may be displayed to advise the driver to try to
perform eco-diving. After displaying the information on the screen,
the navigation processing unit 311 increments the number of the
checkpoint, to which the vehicle will travel next, by 1 (S1111) and
executes the processing again beginning at S1101 to continue the
navigation processing. Before executing the processing in S1101
again, the navigation processing unit 311 may perform the
processing, similar to that in S1107, to suspend the navigation
processing.
If the remaining battery capacity at the current confirmation point
is outside the estimated remaining battery capacity band (S1109:
NO), the navigation processing unit 311 determines whether the
remaining battery capacity is below the estimated remaining battery
capacity band (S1112). If the remaining battery capacity at the
current confirmation point is below the estimated remaining battery
capacity band (S1112: YES), the navigation processing unit 311
displays the information, which indicates that the consumption
amount is larger than the amount that is consumed according to the
scheduled battery consumption pace estimated in the route search
result, on the output device 304 of the display terminal 101
(S1113). After that, the navigation processing unit 311 performs
the route search request processing, shown in FIG. 8, again (S1114)
because there is a possibility that the battery exhaustion will
occur before the vehicle arrives at a charging station or a transit
location if the vehicle continues driving at the current traveling
pace.
If the remaining battery capacity at the current confirmation point
is above the estimated remaining battery capacity band (S1112: NO),
the navigation processing unit 311 displays the information on the
output device 304 to indicate that the user is performing
eco-driving better than scheduled. After that, the navigation
processing unit 311 displays the information on the output device
304 to ask the user whether to search for an optimal route that
requires a shorter traveling time (including the charging time)
because the battery capacity is sufficient (S1115). The navigation
processing unit 311 accepts a user option from the input device 303
(S1116) and, if the user selects to perform a route re-search
(S1116: YES), performs the route search processing, shown in FIG.
8, again (S1114).
If the user does not select to perform a route re-search (S1116:
NO), the navigation processing unit 311 executes the processing
again, beginning at S1101, to continue the navigation
processing.
If the user does not enter an option in response to the information
in S1115 for a predetermined time, the display terminal 101 may
automatically determine that the user selects, or does not select,
to perform a re-search. Whether to perform a route re-search may be
determined, not on the period of time the user does not enter an
option, but on the traveling distance of the electric vehicle
102.
If the estimated remaining battery capacity at a checkpoint is
indicated, not by the band information, but by a border value
(border), one possible method is to execute, not the processing in
S1109, but the processing in S1112 when the navigation processing
unit 311 determines in S1104 that the vehicle has passed the
checkpoint (S1104: No).
The processing in S1103, S1104, and S1105 may be performed, not by
the navigation processing unit 311 of the display terminal 101, but
by the telematics center 100. More specifically, the vehicle
information acquired in S1102 is sent to the telematics center 100
to allow the telematics center 100 to perform the processing in
S1103, S1104, and S1105 using the calculated route search result,
and the information on the next checkpoint, obtained in S1105, is
sent to the display terminal 101.
Similarly, the processing subsequent to S1103, S1104, and S1109 may
be performed, not by the display terminal 101, but by the
telematics center 100.
Next, with reference to FIG. 12 to FIG. 15, an example of the
screen of a display terminal is described where the input device
303 and the output device 304 of the display terminal 101 are
implemented by the same medium such as a touch panel.
FIG. 12 is a diagram showing an example of the route search setting
and route search result screen of the navigation system for an
electric vehicle. This screen is displayed on the output device 304
of the display terminal 101.
In FIG. 12, the following are output on the output device 304: an
area 1200 in which a starting point is entered, an area 1201 in
which a destination is entered, an area 1202 in which a start time
is entered, an area 1203 in which the remaining battery capacity of
the electric vehicle 102 at the starting point is entered, an area
1204 in which the battery capacity of the electric vehicle 102 is
entered, an area 1205 in which the remaining battery capacity when
the vehicle arrives at the destination is specified, a button 1206
that triggers the issuance of a shortest route search request from
the display terminal 101 to the telematics center 100, a button
1207 that triggers the start of the navigation processing in S805
performed by the display terminal 101, a map 1208, an image 1209
that indicates the position of the starting point, an image 1210
that indicates the position of the destination, an image 1211 that
indicates the position and type of a charging station, and a
shortest route search result 1212 that is based on the specified
starting point, destination, start time, confirmation-point
remaining battery capacity, battery capacity, and estimated
remaining battery capacity at the arrival time. An image 1213,
which indicates the position of a checkpoint, is also displayed in
the shortest route search result.
A starting point can be registered in the starting point entry area
1200, for example, by specifying the latitude and longitude
information. After the starting point is registered, the image 1209
indicating the position of the starting point is displayed on the
map 1208.
A destination can be registered in the destination entry area 1201,
for example, by specifying the latitude and longitude information.
After the destination is registered, the image 1210 indicating the
position of the destination is displayed on the map 1208.
The display terminal 101 may have the point search function, in
which case the user enters the character string of a facility name
to search for the specified facility and specifies the latitude and
longitude information on the starting point and the destination.
Similarly, the telematics center 100 may have the point search
function, in which case the display terminal sends the character
string of a facility name to the telematics center and inquires
about the search result.
The remaining battery capacity and the battery capacity at the
starting point may be displayed automatically by the display
terminal 101 using the vehicle information received in S801.
The shortest route search result 1212 is displayed along a road on
the map according to the search result. If there is a transit
charging station, the color of the image 1211 of the charging
station is inverted to make it easy to understand that the charging
station is a transit charging station.
It is also possible to allow the user to specify a plurality of
transit points from the input device 303 in the order in which the
vehicle will reach. If there are transit points, a route search
request is sent to the telematics center 100 to inquire about the
three (from the starting point to a transit point, between transit
points, and from a transit point to the destination) and the route
search results are combined and displayed.
When outputting the screen on the output device 304, the display
terminal 101 may send an inquiry to the electric vehicle 102 to
display the position information on the electric vehicle 102, as
well as the images, on the map 1208 or to display the position
information on the electric vehicle 102 as the initial value of the
starting point entry area 1200 using the latitude and longitude
information or the address.
FIG. 13 is a diagram showing an example of the navigation screen of
the navigation system for an electric vehicle that is displayed on
the output device 304 of the display terminal 101.
In FIG. 13, the following are displayed on the output device 304: a
map 1300, an image 1301 that indicates the current time, an image
1302 that indicates the current position of an electric vehicle
that is traveling, an image 1303 that indicates the route search
result overplayed on the map, an image 1304 that indicates the
position of the next checkpoint, the destination or a transit
charging station 1305 to which the vehicle is currently traveling,
an image 1306 that indicates the detailed information on the
checkpoint, an image 1307 included in the image 1306 for
illustrating the remaining battery capacity and the estimated
remaining battery capacity band at the checkpoint, an image 1308
that illustrates the confirmation-point remaining battery capacity
when the vehicle passed the checkpoint, and an area 1309 in which
the characters describing the checkpoint or the route guidance are
displayed.
In the map 1300, the map data included in the map DB 320 of the
display terminal 101 is displayed. The map data includes the road
information and the facility information including the information
on charging stations. This information may also be obtained by
sending an inquiry to the telematics center 100.
In the image 1305, for a point (one of a transit point, the
destination, and a transit charging station) to which the vehicle
is traveling, the remaining traveling distance to that point and
the expected arrival time are displayed. When the point is a
transit charging station, the type of the charging station, the
charging time (CT) at the transit charging station, and the
estimated remaining battery capacity (SoC) at an arrival time are
displayed.
In the image 1306, for the checkpoint that the vehicle will pass
next, the remaining battery capacity band of the checkpoint is
displayed in a visualized format. In addition, the
confirmation-point remaining battery capacity, which is the
predicted value at checkpoint-passage time calculated in S1005, is
displayed.
In the image 1307, the battery capacity as well as the estimated
arrival-time remaining battery capacity and the estimated remaining
battery capacity band, both of which are calculated in S1105, are
displayed. A battery value, though displayed as the percentage (%)
of the battery capacity in FIG. 13, may also be displayed by an
absolute value, for example, in terms of kWh or may be displayed as
a value in terms of distance (km) using the electric mileage of the
electric vehicle 102 being navigated.
The image 1308 indicates the relative position of the estimated
remaining battery capacity at the checkpoint arrival-time
calculated in S1105 with respect to the image 1307 that indicates
the estimated remaining battery capacity band. In the example in
FIG. 13, it is presumed that the vehicle will pass the next
checkpoint when the remaining battery capacity is 34%, indicating
that the presumed value falls in the remaining battery capacity
band from 27% to 43%.
In the area 1309, for the route search result displayed in the
image 1303, the information on the direction in which the electric
vehicle 102 is to travel or the information on an intersection at
which the vehicle is to turn right or left is displayed.
In the area 1309, the information on the charging stations around
the current point, for example, the charging station with the
shortest traveling distance from the current point, may be
displayed. For example, the traveling distance to that charging
station and the required power consumption are displayed.
When the checkpoint information is displayed, not by the remaining
battery capacity band, but by border information represented by a
border value, it is possible to display only a borderline, in place
of a strip-shaped image, in the image 1307.
FIG. 14 is a diagram showing an example of the navigation screen of
the navigation system for an electric vehicle that is displayed on
the output device 304 of the display terminal 101.
FIG. 14 shows the navigation screen that is displayed when the
confirmation-point remaining battery capacity at a
checkpoint-passage time is within the estimated remaining battery
capacity band at the checkpoint. In addition to the items shown in
FIG. 12, the message, which indicates that the remaining battery
capacity at a checkpoint-passage time is within the remaining
battery capacity band at the checkpoint, is displayed in an area
1400 where a message about the checkpoint is displayed. An image
1401 that indicates the confirmation-point remaining battery
capacity, which is the actual measurement value at checkpoint
passage time, is also displayed. In addition, because the remaining
battery capacity at the checkpoint passage time is 30% that belongs
to the lower half of the remaining battery capacity band 27% to
43%, the message advising the user to try to perform eco-driving is
displayed in the area 1400.
It is also possible that the screen for determining whether to
perform a route research, such as the one shown later in FIG. 15,
is displayed and, when the user selects to perform re-search, the
display terminal 101 performs research.
FIG. 15 is a diagram showing an example of the navigation screen of
the navigation system for an electric vehicle that is displayed on
the output device 304 of the display terminal 101.
FIG. 15 shows the navigation screen that is displayed when the
confirmation-point remaining battery capacity at a
checkpoint-passage time is larger than the estimated remaining
battery capacity band at the checkpoint. In addition to the items
shown in FIG. 12, the message, which indicates that the remaining
battery capacity at a checkpoint-passage time is larger than the
remaining battery capacity band, is displayed in an area 1500 where
a message about the checkpoint passage is displayed. An image 1501
that indicates the confirmation-point remaining battery capacity,
which is the actual measurement value at checkpoint passage time,
is also displayed. In addition, because eco-driving is performed
more smoothly than expected in the route search result, the message
is displayed in the area 1500, indicating that a route, which
requires a traveling time (including the charging time) shorter
than that in the route search result at the starting point, may be
searched for. The user, who browses the area 1500, selects "Yes" or
"No" displayed in an area 1502 to indicate whether to perform
re-search. If "Yes" is selected, the display terminal 101 performs
route research.
It is also possible that, instead of outputting an option to select
an option to perform re-search, it is also possible that the
display terminal 101 unconditionally sends, or does not send, a
route re-search request to the telematics center 100.
FIG. 16 is a diagram showing an example of the navigation screen of
the navigation system for an electric vehicle that is displayed on
the output device 304 of the display terminal 101.
FIG. 16 shows the navigation screen that is displayed when the
confirmation-point remaining battery capacity at a
checkpoint-passage time is smaller than the estimated remaining
battery capacity band at the checkpoint. In addition to the items
shown in FIG. 13, the message, which indicates that the remaining
battery capacity at a checkpoint-passage time is smaller than the
remaining battery capacity band, is displayed in an area 1600 where
a message about the checkpoint passage is displayed. An image 1601
that indicates the confirmation-point remaining battery capacity,
which is the actual measurement value at checkpoint passage time,
is also displayed. In addition, because eco-driving is not
performed as assumed in the route search result, battery exhaustion
may occur before the vehicle travels to the destination, a transit
point, or a transit charging station if the traveling continues
according to the route search result at the starting point.
Therefore, the display terminal 101 performs the route re-search
and displays an image 1602 that indicates that the route re-search
is performed.
As in the area 1502 in FIG. 15, an option to select whether to
perform the research for an optima route may also be displayed to
prevent the battery exhaustion.
According to this embodiment, the user who is traveling in an
electric vehicle can easily determine whether the vehicle traveling
state (current remaining battery capacity) is better than the route
search result calculated by the telematics center. In addition, the
user can identify where the current remaining battery capacity
stands in the remaining battery capacity band at a checkpoint.
Therefore, even if the route re-search is performed to prevent
battery exhaustion, this ability allows the user to easily guess
the cause, thus reducing the worry during the navigation.
Another embodiment of a navigation system for an electric vehicle
is described below. Instead of the method in which the confirmation
position coordinates are set at a regular interval based on the
time or the distance such as that described in FIG. 9, the method
described below with reference to FIG. 17 may also be used as a
method for determining the confirmation position coordinates of
checkpoint information that are added to the route search
information. More specifically, in FIG. 17, the shortest route
search is performed first based on the current remaining battery
capacity in the same way as in S908 (S1700).
Next, the shortest route search unit 212 sets n to 1 to initialize
the checkpoint number (S1701) and then, for the actual remaining
battery capacity R used in the route search in S1700, performs the
shortest route search by setting the remaining battery capacity to
R.times.(1-n/T) (S1702). The value of the integer T, for which an
appropriate value is set by the server, may also be specified by
the user when issuing a route search request. The shortest route
search unit 212 compares the route search result, calculated in
S1702, with the route search result when the remaining battery
capacity is R.times.(1-(n+1)/T) to derive a point at which the
route search results do not match, that is, derives a junction
intersection on the route (S1703). After identifying the road link
ID 710 of the link before the vehicle enters the junction
intersection, the shortest route search unit 212 determines the
remaining battery capacity band at the checkpoint in the same
manner as in S903 to S905 (S1704). After the derivation of the n-th
checkpoint information is completed, the shortest route search unit
212 adds 1 to n (S1705) and checks if n is smaller than the integer
T to determine whether the next checkpoint is to be derived
(S1706). If n is smaller than T (S1706: YES), the shortest route
search unit 212 re-executes the processing beginning at S1702 to
generate the next checkpoint information. If n is equal to or
larger than T, the shortest route search unit 212 includes the
extracted (n-1) pieces of checkpoint information in the route
search result and terminates the processing (S1707).
For example, when T is set to 10 in the method described above, the
remaining battery capacity at the starting point becomes 0.9 times,
0.8 times, . . . , 0.1 times of the actual value and, according to
this change, the transit charging station the vehicle is to visit
may be changed to a new transit charging station. In such a case,
the method described above allows a confirmation point to be
determined by setting the point of route switching to the position
of the new transit charging station as a checkpoint.
Although the 1.0 times or less of the remaining battery capacity is
used in S1702, 1.0 times or more of the remaining battery capacity
may also be used.
The expression of the remaining battery capacity in S1702 may be an
expression that changes based, not on the multiplication factor of
the remaining battery capacity, but on the battery capacity. More
specifically, the expression for determining the remaining battery
capacity according to n may be as follows: R-C*(1-n/T) or
R+C*(1-n/T) where C is the battery capacity of the electric
vehicle.
The checkpoint information to be included in the route search
result may be not only the information extracted in S1700 to S1706
but also a combination of a part or all of the checkpoints
extracted in S900 to S907.
FIG. 18 is a diagram showing an example of the navigation screen of
the navigation system for an electric vehicle that is displayed on
the output device 304 of the display terminal 101 according to the
checkpoint confirmation-point coordinate determination method shown
in FIG. 17.
In addition to the items on the screen shown in FIG. 13, the screen
shown in FIG. 18 includes the two additional images 1800 (CSL) and
1801 (CSU). The image 1800 indicates the identifier of a transit
charging station that the vehicle is to visit due to a change in
the route when the remaining battery capacity is smaller than the
remaining battery capacity band, and the image 1801 indicates the
identifier of a transit charging station that the vehicle is to
visit due to a change in the route when the remaining battery
capacity is larger than the remaining battery capacity band. This
information allows the user to confirm whether the vehicle is
currently traveling at the battery consumption pace assumed by the
route search result and, in addition, to reference the information
on a new transit charging station information based on the
assumption that the battery consumption pace is higher than
expected or the user has been performing eco-driving more
efficiently than expected, thus reducing the worry about a sudden
changed in the route.
The screen may be configured in such a way that, when the user
touches the image 1800 or the image 1801, the position information,
availability information, and near-by facility information on the
charging station are displayed. It is also possible to display an
option, which allows the user to change the route to a route on
which the charging station is included, and to request the
telematics center 100 to perform the route search again when the
user selects to change the route.
The information may be displayed, next to the image 1800 and the
image 1801, to indicate how the total traveling time (including the
charging time) will change when the route is changed to a route
including the charging station.
In another embodiment of the route search system for an electric
vehicle, the display terminal 101 may have the function of the
telematics center 100, in which case the display terminal 101
performs the route search and displays the route search result on
the output device 304 by sending an information request directly to
the electric vehicle 102 or the charging station 103. The display
terminal 101 may also perform all processing within itself by
receiving the information on the electric vehicle 102 and the
charging station 103 via the input device 303.
In still another embodiment of the route search system for an
electric vehicle, the display terminal 101 may be integrated into
the electric vehicle 102 in which case the electric vehicle 102 has
the function of the display terminal 101. In this case, a device
such as a car navigation device may be used in place of the display
terminal 101.
It should be further understood by those skilled in the art that
although the foregoing description has been made on embodiments of
the invention, the invention is not limited thereto and various
changes and modifications may be made without departing from the
spirit of the invention and the scope of the appended claims.
* * * * *